sorry, I thought you meant that the headstock was moving on the bed. It's kind of hard to tell in that video. The Camera Is moving so much that there is not a good reference. If the shaft is moving in and out, your take-up nut on the left end of the Spindle is probably loose. The spindle is held steady only on the left side bearing. Right side bearing is left to float. Note: make sure you still have the fiber washer between the take-up not and the bearing journal. Alternatively you can use a needle bearing here. But there must be A bearing surface between the take-up not in the bearing journal. Loosen up the clamping screw, Then tighten the take-up nut until you feel drag, then back off just a little bit until it turns freely. Retightened the locking screw. if this does not fix the problem, please give us a video without all the camera movement. Focus on one spot, then demonstrate the problem. We can tell more about what's going on.
stay safe and have fun.
Joe.
